Step 2: Modeling the strawberry II

Disable Proportional Editing, in Edit mode select all the vertex (Ctrl+A) and use the poke faces command (Alt+P). Now your model will look like the image below. Change selection mode from vertex to edge (Ctrl+TAB) and select the 4 edge shown in the second picture below. Open select menu and click on Similar > Face Angles, inverse the selection (Ctrl+I) and delete edges (X > edge). Select all (Ctrl+A ) and press F to create missing faces. Now you should have a model like the fourth image below.